I was searching the site for a dedicated PSP-2 thread and found a number of really informative posts sparsely placed all around. I understand that much of this might be common knowledge to those familiar with this preamp over the years, but since there doesn't appear to be a central thread I have compiled relevant info here.

I set up my computer to generate a steady tone, then from my DAC (Headamp Pico), I fed an unbalanced signal to my V3, and then SPDIF out to my PMD-661. I adjusted the signal to a specific level on the meter using the gain and the trim on the V3. Then I placed the PSP-2 between the DAC and V3 and measured the signal increase. I used the balanced outs on the PSP-2.

So there probably is a pretty big margin of error and it would be nice to get an actual number for the peak value instead of estimating it by eye. I would say +/- 5 dB. I tried feeding the signal to another computer but couldn't really get the digital in or line in to work.

Second photo, on the left, the red/blue switch is one of two (the other is out of view below). These are for switching between 24 and 48 volts phantom powering.

In the top left of the board, what are those trimpots for? Would these be for input (or output) finer gain adjustments?

It's truly amazing how compact and tightly put together this preamp is. I would have taken a picture of the other side, but it's basically just a metal wall that extends beyond the battery compartment. It appears there are three total boards, all facing in towards one another in a sandwich.

Thanks for starting thread and posting pics. Anyone running there's on a 5v usb battery? When I set mine up that way with fresh charge, low level battery light flashes as soon as you power the unit on. Haven't run any tests this way. Any thoughts? The usb battery can do 5-12v but it senses voltage automatically, no way to set voltage you want. Weirdness

I've been using a USB battery to power my PSP2 for the longest time. I've used a variety of packs, from the older ones that supply 5V, 500 mA, to the newer ones that supply around 2 A per port.

Check if it's your battery. Try powering the PSP2 by using the same cable plugged into your computer. If your battery is fine (ie., it can charge other devices like a phone), it might also be the cable too. Worst case scenario is if it's the preamp. Then you'll have to send it in to get checked out.

Do you have any way to measure if the PSP2 is supplying the correct voltage to your mics (ie., a multimeter?)

Thanks for starting thread and posting pics. Anyone running there's on a 5v usb battery? When I set mine up that way with fresh charge, low level battery light flashes as soon as you power the unit on. Haven't run any tests this way. Any thoughts? The usb battery can do 5-12v but it senses voltage automatically, no way to set voltage you want. Weirdness

In addition to my trim pot question above, has anyone ever experienced a difference in output levels (via XLR and 1/8” stereo outs)? This occurs with both mic and line-in sources, with output gains set to 0 dB.

I'm not 100% sure, but I think the mini out isn't as hot as the xlr outputs. And I checked my usb battery output. It was 5.2v. Light still flashes on psp2. Talked to VARK audio and they didn't really have an answer for me. Cable I'm using is a short right angle usb to power cable. Seems they designed to pre to run at 9v optimally thus the 6aa battery sled. Might hook up rig tonight and record to see if there's any audible noise with low batt light flashing. Wish I could find a tiny 9v usb battery or one that you can adjust output manually. Mine senses voltage automatically and adjusts.

Woops, I should clarify. I meant a difference in levels between channels L and R. This difference in channel outputs is reflected on both XLR and 1/8” outputs. My right channels are significantly hotter.

You are correct that an overall difference would be expected between the 1/8” (unbalanced) and XLR (balanced) outputs.

Woops, I should clarify. I meant a difference in levels between channels L and R. This difference in channel outputs is reflected on both XLR and 1/8” outputs. My right channels are significantly hotter.

You are correct that an overall difference would be expected between the 1/8” (unbalanced) and XLR (balanced) outputs.

I have a set of 48V PFA's that output L/R differently by a very noticeable amount but not my PSP2. They seem pretty even to me. I love this pre too. My new favorite thing about it is running the XLR outs to the AD2K+ and also running a M10 off the 1/8 out. Just so easy to have a backup now that takes up virtually no additional bag space.